Combination handling and conveying apparatus

ABSTRACT

In one exemplar embodiment, an apparatus for handling and conveying materials is disclosed having a movable chassis, a longitudinally extendable conveyor assembly mounted on the chassis, the conveyor having a projecting loading end capable of limited longitudinal and arcuate vertical movement to a position immediately adjacent the location of the material being handled. An articulated boom assembly is rotatably mounted on the chassis with the movable free end carrying a pushing and pulling blade for loading the material unto the loading end of the conveyor.

This is a division of application Ser. No. 148,822, filed May 12, 1980now U.S. Pat. No. 4,379,672.

BACKGROUND OF THE INVENTION

This invention relates to apparatus for excavating, handling and loadingmaterials. More particularly, the invention relates to a handling andloading apparatus carrying a longitudinally extendable conveyor forloading materials forward of the apparatus onto the conveyor for removalrearwardly of the loading apparatus.

In excavating and handling topsoil, sand, gravel, aggregates, coal, andcrushed ores and the like, including bulk stored grains, it is generallynecessary to load and move large volumes of such material and excesstime and motion wasted in loading such material greatly adds to its costof production and handling. In addition, it is difficult to unload suchmaterials, or other similar unconsolidated granular materials, fromvessels such as ships or barges from a dock which is generally at ahigher elevation than the deck of the vessel. In addition, the edge ofthe dock limits forward movement of the loading means and thus limitsaccessibility to the vessel.

The known prior art includes draglines, bulldozers, cranes, bucketexcavators and front-end loading machinery for scooping up and loadingsuch material into a fixed conveyor system or into another vehicle suchas a truck or rail-car for transportation. Self-propelled excavating andconveying machines have been utilized as exemplified by the apparatusdisclosed in U.S. Pat. No. 2,366,480 (Beckwith); U.S. Pat. No. 2,384,242(Fitch); U.S. Pat. No. 2,518,964 (White); U.S. Pat. No. 3,206,048(Weiss); U.S. Pat. No. 3,241,693 (Stroker); U.S. Pat. No. 3,517,840(Schneider); U.S. Pat. No. 3,547,287 (Cunningham); and U.S. Pat. No.3,720,331 (Kamner).

However, all of such prior art utilizes scoops and buckets to pick upand load the material onto a conveyor system or other vehicle fortransport. None of the prior art in the above-recited patents thatutilize built-in conveyor systems discloses a conveyor apparatusutilizing a conveyor system that is maneuverable forward of theapparatus both longitudinally and in limited arcuate vertical movementto emplace the loading end of the conveyor in any desired position incontact with the material at differing levels, even below the level ofthe apparatus itself, in order that a handling means mounted on theapparatus can continuously move material onto the loading end of theconveyor. Such continuous loading without the necessity of the bucket orshovel to lift the material and swing it to a second position to unloadthe material can save a considerable amount of time in handling suchmaterials.

Accordingly, one primary feature of the present invention is to providea handling and conveying apparatus carrying a longitudinally extendableconveyor assembly that is also adapted for limited arcuate verticalmovemenet.

Yet another feature of the present invention is to provide a conveyormeans having a loading end positionable longitudinally and verticallyforward of the apparatus in contact with the material to be moved forfacilitating direct loading of the material.

Yet another feature of the present invention is to provide anarticulated boom carrying a blade that is positionable forward of theapparatus to cooperate with the movable loading end of the conveyorabove described in order to provide nearly continuous loading of thematerial onto the loading end of the conveyor with a minimum of lostmotion.

Still another feature of the present invention is to provide means ofmoving the boom and handling means and/or the conveyor means forwardlyof the apparatus to increase the reach of the apparatus from a fixedlocation.

SUMMARY OF THE INVENTION

The present invention remedies the problems of the prior art byproviding an apparatus for handling and conveying material, by providinga vehicle that includes the above mentioned features. In accordnace withone principle of this invention, an apparatus for handling and conveyingmaterial is disclosed comprising a chassis adapted for at least limitedlateral movement, means for moving the chassis, longitudinallyextendable conveyor means attached to and supported by the chassis andadapted for limited vertical arcuate movement with respect thereto, theconveyor means having a loading end projecting forwardly from thechassis and a discharge end projecting rearwardly from the chassis, theloading end movable longitudinally and arcuately to a position forwardof the chassis and into contact with the materials, a platform rotatablymounted on the chassis in a position above the conveyor means, means forhorizontally rotating the platform with respect to the chassis, anarticulated boom means mounted on the platform for rotation therewithand having a free extending end, and handling means attached to the freeextending end of the boom means and cooperating with the loading end ofthe conveyor means for continuously moving the materials unto theconveyor means.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above-recited advantages andfeatures of the invention are attained can be understood in detail, amore particular description of the invention may be had by reference tospecific embodiments thereof which are illustrated in the appendeddrawings, which drawings form a part of this specification. It is to benoted, however, that the appended drawings illustrate only typicalembodiments of the invention and therefore are not to be consideredlimiting of its scope for the invention may admit to further equallyeffective embodiments.

In the drawings:

FIG. 1 is a side elevation of one embodiment of the handling andconveying apparatus according to the present invention.

FIG. 2 is a side elevation of the self-propelled handling and conveyingapparatus of FIG. 1 shown loading material at a level below the level ofthe apparatus onto the conveyor.

FIG. 3 is a top plan view of the apparatus shown in FIG. 1.

FIG. 4A is a perspective view of a loading blade for handling thematerial.

FIG. 4B is a top view of the blade shown in FIG. 4.

FIG. 5 is a vertical cross-sectional view of the conveyor taken alonglines 5--5 of FIG. 1.

FIG. 6 is a partial detail view of the conveyor system utilizing anotherembodiment of a driving means to extend and retract the conveyor.

FIG. 7 is a top plan view of a second embodiment of the handling andconveying apparatus in which the conveyor is mounted on the side of theapparatus chassis.

FIG. 8 is a partial detail side view of the side mounted conveyor systemshown in FIG. 7.

FIG. 9 is a side elevation of a third embodiment of the handling andconveying apparatus according to this invention.

FIG. 10 is a partial front elevation and vertical crosssection of yetanother embodiment of the handling and conveying apparatus in which theconveyor system is also mounted for limited horizontal arcuate movement.

FIG. 11 is a top partial detail view of one drive means for moving theboom platform horizontally in the embodiment of FIG. 9.

FIG. 12 is a partial side detail view showing a cable/winch apparatusfor laterally moving the boom platform in another embodiment of FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1, 2, 3, 4 and 5, a preferred embodiment of thehandling and conveying apparatus 10 is shown. The apparatus 10 comprisesa generally inverted U-shaped chassis 12 of conventional design for anexcavator, except that is is much "higher" or has a greater groundclearance, to accommodate the underslung conveyor assembly 40. Theapparatus uses a chassis 12 of the "crawler" type of self-propelledvehicle utilizing an endless track 14 driven by a motor (not shown) in aconventional manner. A platform 20 (including a vehicle "cab" for anoperator) is mounted for rotation with respect to the chassis 12 in aconventional manner by means of a gear 16 driven by a pinion gear 17.The motor for driving pinion gear 17 is not shown, but can be ofconventional hydraulic or electrical design. The gear 16 and necessarysupporting plate (not shown) are mounted for rotation in a conventionalmanner in the top surface 18 of chassis 12.

A conventional type articulated boom assembly 21 is hinged to thestructure of platform 20 for limited vertical arcuate movement forperforming the necessary excavating and scooping movements. Boomassembly 21 includes a first boom section 22 hinged at end 23 to theplatform structure 20 and supported and actuated by a pair of mainhydraulic cylinders 24 attached conventionally by means of pivot pins25. A second boom member 26 in hinged to the first boom member 22 byhinge pin 27 with an upper end 29 extending above first boom member 22.A hydraulic cylinder 28 is attached to member 22' of boom member 22 andpivotally attached to the extremity of end 29 of boom member 26 by meansof a hinge pin 29. Boom member 26 thus is adapted for moving arcuatelyabout hinge pin 27 with respect to the first boom member 22.

A handling means 30 is hinged to the lower end of the second boom member26 by means of hinge pin 36 and mounting lugs 34 disposed on thehandling means 30. A hydraulic cylinder 32 is disposed between member26' of boom member 26 and lugs 35 disposed centrally of means 30 andspaced adjacent to lugs 34. The piston of cylinder 32 is pivotallymounted to lugs 35 by means of pivot pin 38. The action of boom assembly21 is conventional in that cylinders 24, 28 and 32 co-act to articulateboom members 22 and 26 and the handling means 30. In the view of FIGS.1, 2 and 3, the handling means 30 is shown preferably as a curved"scooping" blade. However, a bucket could also be used as can any otherdesign of a means for continuously moving the material unto theconveyor.

A conveyor assembly 40 is slung under platform 20 and the top surface 18of chassis 12 and is supported for limited vertical rotational movementabout axles 44 fixed to chassis 12 and journaled to the conveyor cradle42 as shown in FIG. 5. Bracket members 46 are attached to the forwardends of cradle 42 and extend upwardly therefrom. A pair of conveyortilting hydraulic cylinders 48 are attached pivotally to lugs 53 onchassis 12 by pins 52 and to bracket member 46 by pins 50. Cylinders 48are operable to lower or raise the loading end of conveyor assembly 40to a position into intimate contact with the material being handled.

Cradle 42 includes channel-type side rails 42' and a crossbracing 43welded to the spaced apart rails 42' to provide structural strength andrigidity. Disposed longitudinally within cradle 42 is a generallyrectangular conveyor structure 57 comprising side frame members 54 andstructural cross-frame members 55 and 55' (See FIG. 5). Conveyorstructure 57 is mounted within cradle 42 for coaxial longitudinalmovement with respect thereto as will be hereinafter further described.A pair of hydraulic cylinders 56 are attached rearwardly between cradle42 and the rear end of structure 57 to provide a moving means forlimited longitudinal movement of conveyor structure 57 with respect tocradle 42.

Bracket and frame members 64 and 66 are fixed to the forward extendingends of frame members 54 to support a shallow, generally rectangularmaterial-receiving bin or hopper 68. The forward end of hopper 68terminates in a generally flattened edge 70. Bin 68 has a generallyrectangular opening 69 centrally disposed therein to receive theconveyor belt 58 that traverses the length of the conveyor structure 57.Conveyor belt 58 may preferably be of the "trough" type of conveyor andis supported by a plurality of rollers 60 and 60' spaced along andattached to frame members 54 and 55 (See FIG. 5). A motor drive 62drives the endless conveyor belt 58 to move material from bin 68 fordischarge rearwardly of apparatus 10.

As may be seen in greater detail in FIG. 5, the conveyor cradle 42 ishinged by means of axles 44 for limited vertical arcuate movement withrespect to chassis 12. Cradle 42 is generally a rectangular box-likestructure (as previously described), open on opposite, longitudinalends. Pairs of spaced rollers 45 are mounted on base 43 by means ofbrackets 47 adjacent the side walls 42' and longitudinally spaced thelength of cradle 42 (See FIG. 5). The spaced side rails 54 of conveyorstructure 57 are disposed on the longitudinally disposed rollers 45 forpermitting longitudinal movement of structure 57 along the rollers forthe purpose hereinabove described. Roller brackets 59 and 59' areattached to the frame members 54 and/or 55 and project upwardlytherefrom to support a trio of rollers 60 and 60' by means of pins 61 ina conventional manner to form a "trough" type conveyor having agenerally shallow U-shaped cross-section for supporting belt 58. Inaddition, rollers 65 may be disposed between brackets 63 and rails 54 inthe space between cross-braces 55 and 55' to provide support for thereturn portion of the conveyor belt 58.

As shown in FIG. 2, the apparatus 10 is positioned on a first groundlevel 11 and the bin 68 of conveyor assembly 40 positioned to contactearth materals 13 such as soil, sand, gravel or ore 13 located onanother level 15. Conveyor assembly 40 may be positioned to place bin 68at the desired height for easy moving of material 13 into the bin fortransfer by the conveyor belt 58 to the rear of apparatus 10. Cylinders56 may be used to extend or retract conveyor structure 57 with respectto cradle 42 as shown in FIG. 3, thereby moving conveyor bin 68longitudinally with respect to boom assembly 21 as shown by the dottedlines.

Of course, the apparatus 10 can use a conventional excavator scoop orbucket, however, it has been found preferable to use a wide curved blade30, shown in greater detail in FIGS. 4A and 4B. Blade 30 is a generallycurved, U-shaped metal blade having curved upper and lower edges 33 andU-shaped ends 31. A pair of boom mounting lugs or brackets 34 are fixedto the forward central area at the top of the blade and carry mountingholes 36' for receiving pivot pin 36 for pivotally attaching blade 30 tothe end of boom section 26. A second pair of lugs 35 are fixed to theblade outwardly of lugs 34 and carry holes 38' for receiving pivot pin38 for pivotally attaching the piston rod of cylinder 32. Of course,other handling means 30 may be utilized as desired.

FIG. 6 shows another embodiment of a means of moving conveyor structure57 with respect to conveyor cradle 42. In the partial top view shown inFIG. 6, the spaced side rails 54 and crossbraces 55 (55') are shown,with rails 54 adopted for longitudinal rolling movement with respect tocradle 42 on the spaced, opposed pairs of rollers 45. A motor 72,preferably an electric or hydraulic motor, is mounted on a cradlecross-brace member 43 and drives a threaded shaft 74 that may be coupleddirectly to motor 72 or driven through a suitable gear-box (not shown).Drive shaft 74 is supported and journaled in at least a pair of blocks73 and 76 attached to frame members 43 of cradle 42. Shaft 74 passesthrough threaded follower assemblies 75 attached to at least a pair ofcross-braces 55' (See FIG. 5). When motor 72 is actuated to turn shaft74 in one direction, the rotating screw threads engage the followers 75and move conveyor structure 57 in a desired direction. When motor 72 isreversed, the rotation of threaded shaft 74 is reversed and drives theconveyor 57 in the opposite direction.

Referring now to FIGS. 7 and 8, another embodiment 90 of the apparatusis shown. In embodiment 90 the crawler vehicle chassis 12 may be of moreconventional height and design since the conveyor assembly 40 is mountedto one side of chassis 12. Platform and cab 20 are mounted forrotational movement on chassis 12 as hereinabove described for apparatus10. However, projecting transversely from one side of chassis 12 arestructural braces 88 supporting a projecting axle or beam 84. Conveyorcradle 42 is mounted for limited vertical rotational movement on axle orbeam 84 by means of a bearing and shackle assembly 86. A transverselyprojecting bracket 80 and supporting brace members 82 are fixed tochassis 12 above track 14 and project transversely over the top ofconveyor assembly 40. The conveyor vertical attitude adjusting cylinders48 are attached at one end to bracket 80 projecting from chassis 12 andto the brackets 46 attached to cradle 42. The cab 20 and boom assembly21 must be slightly rotated to the side to register blade 30 withreceiving bin 68 for accepting loose material as hereinbefore described.It may be desirable to modify the mounting lugs 34 and 35 of blade 30for setting them at an offset angle as shown at 34' and 35' in FIG. 7and thereby enabling blade 30 to be offset at an angle with respect toboom assembly 21 for making it easier to scoop material longitudinallyinto bin 68.

One advantage of the side mounting of conveyor assembly 40 is that itcan readily be mounted on an existing standard excavator chassis, andcan be designed to permit greater downwardly arcuate movement ofconveyor assembly 40 and receiving bin 68, since the rear clearance ofthe conveyor under chassis 12 is not a factor as it is in theembodiments shown in FIGS. 1-5.

FIG. 9 illustrates yet another embodiment 100 of the handling/conveyingapparatus according to this invention. This embodiment is particularlysuited for use on water-front docks 105 for off-loading granularmaterial 113 from a vessel 104, such as a barge of the like, moored inwater 107 to piling 103 at a level usually lower than dock 105 andlaterally beyond the dock. In this embodiment, apparatus 100 includes aself-propelled vehicle having a chassis 112 mounted on axles 111 andpropelled by wheels 114 on a pair of spaced rails 109 mounted on dock105. Platform and cab 120 is mounted for rotation relative to chassis112 by means of a gear arrangement 116, as previously described forother embodiments, mounted in the top 118 of chassis 112. Cab 120 isalso mounted for limited horizontal movement with respect to chassis 112by means of a base 120' that is adapted for movement with respect to asled 120". A motor 123 for actuating and moving base 120' with respectto sled 120", as will hereinafter be further described, is mounted on abracket 119.

The construction and operation of boom assembly 121 is identical to thatof boom assembly 21 previously described and will not here be furtherdetailed. A conveyor assembly 40, identical to that previously describedis mounted for limited vertical, arcuate movement with respect tochassis 112 by means of an axle 144 supported by axle support members145 fixed to chassis 112.

In operation, apparatus 100 can move transversely along dock 105 onrails 109 to properly position conveyor 40 and blade 130 with respect todock 105 and vessel 104. As previously described, and as best shown inFIG. 3, receiving bin 68 can be moved longitudinally by means of movingconveyor structure 57 with resepct to cradle 42. In addition, cab 120,carrying boom assembly 121, can move horizontally toward vessel 104, toa position such as that shown by the dotted lines to further extend thereach and range of boom assembly 121 and the handling means 130. Blade130 moves the loose, granular material 113 into bin 68 for movementalong conveyor belt 58 and rear discharge from apparatus 100 ashereinabove previously described for apparatus embodiments 10 and 90. Asvessel 104 is unloaded, the vessel rises in the water as shown at A andconveyor bin 68 must be adjusted to compensate for the change. Thecombination of the longitudinally positionable conveyor 40 and thelongitudinally positionable excavator cab 120 and boom assembly 121,permit a greater degree of handling access and moving and loadingflexibility than heretofore found in the prior art.

FIG. 11 illustrates in greater detail the means of moving cab base 120'with respect to sled 120" as above described with reference to FIG. 9.Sled 120" comprises a rectangular box-like structure having uprightsides 191 and ends 195. Base members of rails 193 are disposedlongitudinally adjacent sides 191 for providing a support and bearingsurface for the cab base plate 120'. Base plate 120' is adapted to slidealong rails or members 193 or to be supported thereon for rollingmovement by suitable rollers (not shown), similar to that desribed withrespect to rollers 45 of conveyor assembly 40.

Motor 123 is mounted on a bracket 119 that is attached to one end ofsled 120" and drives a threaded shaft 190 journaled in bearing blocks192 disposed at opposite ends 195. Fixed to the underside of base 120are threaded follower blocks through which shaft 190 projects. As motor123 rotates shaft 190 in one direction, the threaded follower blocksmove along shaft 190 thus driving base 120 in a desired direction.

Of course, any other suitable means for moving cab 120 with respect tochassis 112 may be utilized, and another such embodiment is shown inFIG. 12. Vehicle cab 120 and attached articulated boom assembly 121(partially shown in dotted lines) are carried by cab base 120' which ismounted on a rail structure 321 for longitudinal movement thereon. Awire cable 328 is centrally disposed between rails 321 and attached toopposite end frames 325. The cable 328 is wound about a cable drum 324which is driven by a motor 322 by means of a chain or belt drive 326.When actuated, motor 322 rotates cable drum 324 is one direction,thereby moving cab base 120' with respect to the base frame 321. Whenthe motor direction is reversed, the cable drum is rotated in theopposite direction and cab base 120' moves in the other direction to adesired position.

FIG. 10 illustrates yet another embodiment 200 of the apparatusaccording to this invention. The apparatus 200 comprises a wheeled orrubber-tired vehicle chassis 212 supported by rubber tires 214 driven bya conventional motor (not shown). A platform and cab 220 is rotatablymounted on chassis 212 by means of a gear 216 driven by a pinion gear217 powered by a conventional power source (not shown) and mounted in aretaining ring 218.

A conveyor assembly 240 is mounted within a generally inverted U-shapedframe structure 213 by means of a pair of axles or pivot pins 244 fixedto cradle structure 242 that permit limited vertical arcuate movement ofconveyor assembly 240 with respect to frame 213 and chassis 212. Thedetails of construction and operation of the cradle 242 and conveyorstructure 257 are identical to that of cradle 42 and conveyor structure57 previously described, and will not here be further described.

Frame 213 is suspended from chassis 212 by means of a support column 215depending from the central top portion of chassis 212 and is adapted forrotational movement on ring bearings 221 retained by flange 219 ofcolumn 215. If desired, the frame 213 may seat directly on flange 219and the mating surfaces provide a bearing surface. An actuating cylinder290 is attached to chassis 212 by means of a bracket 292 and to one sideof frame 213 by means of pin 294. When actuated, cylinder 290 applies alateral force to pin 294 (offset from the center of frame 213) whichforce is translated into rotational motion rotating frame 213 (carryingconveyor assembly 240) about support column 215. In this manner theconveyor assembly 240 may be rotated through a limited degree ofhorizontal arcuate movement in order to reposition the receiving bin 68laterally of the center line through the vehicle. Of course, any othersuitable means of providing limited horizontal rotational movement toconveyor assembly 240 with respect to chassis 212 may be utilized, if itprovides for the ability of conveyor assembly 240 to also includelimited arcuate vertical movement.

While the design of embodiment 200 is ideally suited for large scalehandling and conveying vehicles used in mining, such a design would alsobe useful as another embodiment of the dockside materialhandler/conveyor shown in FIG. 9, and, of course, can be used for any ofthe other handling and conveying uses herein described.

Numerous variations and modifications may be made in the structureherein described without departing from the present invention.Accordinly, it should be clearly understood that the forms of theinvention herein described and shown in the figures of the accompanyingdrawings and illustrative only and are not intended to limit the scopeof the invention.

What is claimed is:
 1. An apparatus for handling loose materials such asgravel, sand or the like, comprisinga generally inverted U-shapedchassis having an upper horizontal base surface, vehicle drive meanscarrying said generally inverted U-shaped chassis for providing groundsupport and propulsion therefor, a platform rotatably mounted on saidupper horizontal base surface of said chassis, means for horizontallyrotating said platform with respect to said chassis and vehicle drivemeans, an elongated articulated boom means mounted on said platform forrotation therewith and for longitudinal extension beyond said chassisand vehicle drive means, said boom means having a free extending end,longitudinally extendable conveyor means mounted on said chassis belowthe level of said platform and adapted for limited arcuate verticalmovement with respect thereto, said conveyor means includinga generallyrectangular cradle member, suspension means cooperating with saidchassis and said cradle member for suspending said cradle member fromsaid chassis and permitting at least limited arcuate vertical movementtherebetween, conveyor assembly disposed longitudinally in said cradlemember and cooperating therewith for permitting longitudinal movementwith respect thereto, said conveyor assembly having a loading endprojecting from said cradle member and said chassis, driving means formoving said conveyor assembly longitudinally with respect to said cradlemember and moving said loading end longitudinally with respect to saidchassis, and positioning means cooperating with said cradle member andsaid chassis for arcuately moving said cradle member in a vertical planewith respect to said chassis and positioning said longitudinally movableloading end into contact with the loose materials for cooperating withsaid free extending end of said boom means, and material handling meansmounted on said free extending end of said boom means and cooperatingwith said conveyor assembly loading end for moving the materials untosaid conveyor means.
 2. The apparatus as described in claim 1, whereinsaid conveyor driving means comprises a pair of hydraulic cylindersattached between the sides of said cradle member and said conveyorassembly for moving said conveyor assembly longitudinally with respectto said cradle member.
 3. The apparatus as described in claim 1, whereinsaid conveyor driving means comprisesa reversable motor mounted on saidcradle member, a threaded drive shaft driven by said motor, and followermeans fixed to said conveyor assembly and engaging said threaded shaftfor moving said conveyor assembly longitudinally with respect to saidcradle when said motor is actuated.
 4. The apparatus as described inclaim 1, wherein said conveyor assembly further includes a dish-shapedreceiving bin attached to said conveyor loading end for cooperating withsaid conveyor assembly for receiving the loose materials from saidhandling means and guiding the materials unto said conveyor assembly. 5.The apparatus as described in claim 1, wherein said handling meanscomprisesa generally U-shaped longitudinally curved blade, and lugmounting means disposed on said blade for pivotal attachment to saidfree end of said boom means.
 6. The apparatus as described in claim 1,wherein said platform cooperates with said chassis horizontal basesurface for permitting said platform limited lateral movement withrespect to said chassis and further includes driving means cooperatingwith said platform and chassis for moving said platform with respectthereto.
 7. The apparatus as described in claim 6, wherein said chassishorizontal base surface includes a pair of spaced rail members disposedlongitudinally of said chassis, and said platform is adapted for slidinglongitudinal movement along said rail members.
 8. The apparatus asdescribed in claim 7, wherein said driving means comprisesa bracketmember mounted between said spaced rails adjacent one end of said rails,a reversable motor mounted on said bracket member, a threaded driveshaft driven by said motor, and follower means fixed to said platformand engaging said threaded shaft for moving said platform longitudinallywith respect to said rails when said motor is actuated.
 9. The apparatusas described in claim 7, wherein said driving meanscomprisescross-brackets disposed between each end of said pair of spacedrails, a rotatable cable drum mounted on said platform, means forreversably rotating said cable drum mounted on said platform and a cablepartially wound on said drum and having a free end disposed between saidrails and attached to opposite ones of said cross-brackets, said cablepulling said platform toward one of said cross-bracket ends of saidrails when said cable drum is rotated.
 10. The apparatus as described inclaim 1, wherein said cradle member comprisesa pair of elongated spacedchannel members with the open channels of each member disposed inopposing relationship, a plurality of spaced structural brace membersattached to said spaced channel members for rigidily holding said sidemembers in said spaced opposing relationship, and bearing means disposedin the lower flange of each of said channel members.
 11. The apparatusas described in claim 10, wherein said conveyor assembly comprisesa pairof elongated spaced side members adapted for sliding longitudinalmovement within said spaced channel members and engaging said bearingmeans, a first plurality of spaced brace members disposed transverselybetween said side members in said spaced relationship, a secondplurality of spaced brace members disposed transversely between saidside members and spaced below said first plurality of spaced bracemembers for leaving a longitudinal space therebetween, said first andsecond plurality of spaced brace members acting to rigidly hold saidside members in said spaced relationship, a plurality of spaced rollerbracket means mounted on said first plurality of spaced brace membersand said side members and projecting upwardly therefrom, a plurality ofconveyor rollers mounted for rotation on said roller bracket means, aplurality of spaced support rollers mounted for rotation between saidside members in said space between said first and second plurality ofbrace members, an endless conveyor belt disposed over and supported bysaid plurality of conveyor rollers for carrying material, the returnportion of said conveyor belt disposed over and supported by saidplurality of support rollers, and means mounted on said brace membersand said side members for driving said conveyor belt over said rollers.12. The apparatus as described in claim 1, wherein said conveyorsuspension means comprises an axle means disposed within said generallyinverted U- shaped chassis and cooperating with said cradle member andsaid chassis for permitting limited rotational motion of said cradlemember.
 13. The apparatus as described in claim 12, wherein saidpositioning means comprises a pair of hydraulic cylinders mountedbetween said chassis and forwardly of said cradle member forrotationally moving said cradle member about said axle means in avertical plane.
 14. The apparatus as described in claim 1, wherein saidconveyor suspension means comprises an axle means projecting from oneside of said chassis and cooperating with said cradle member and saidchassis for permitting limited rotational motion of said cradle member.15. The apparatus as described in claim 14, wherein said positioningmeans comprisesbracket means projecting from said chassis above saidcradle member, and a pair of hydraulic cylinders attached between saidbracket means and forwardly of said cradle member for rotationallymoving said cradle member about said axle means in a vertical plane. 16.The apparatus as described in claim 1, wherein said conveyor suspensionmeans comprisesa mounting column depending from said chassis horizontalbase surface, a generally inverted U-shaped mounting bracketrotationally attached to the depending end of said mounting column andadapted for receiving said conveyor cradle member and said conveyorassembly, and axle means disposed between said cradle member and saidgenerally inverted U-shaped mounted bracket for permitting limitedrotational motion of said cradle member.
 17. The apparatus as describedin claim 16, wherein said positioning means comprises a pair ofhydraulic cylinders attached between said mounting bracket and forwardlyof said cradle member for rotationally moving said cradle member aboutsaid axle means in a vertical plane.
 18. The apparatus as described inclaim 16, further including horizontal positioning means disposedbetween said chassis and said conveyor mounting bracket for rotationallymoving said bracket in a horizontal plane about said mounting columndepending end.